Thin chromium alloy films that are patterned with photoresist and etched using reactive ion etching (RIE) are well known in semiconductor processing. For example, chromium alloy thin film resistors are used in integrated circuits and chromium alloy thin films are used to form the light blocking patterns on photo masks.
During the reactive ion etching (RIE) of chromium alloys the resist may be partially etch away. Also chromium alloy etching products may react with the sidewalls of the resist forming hardened sidewalls that form a fence around the chromium alloy device structure. This fence material is resistant to conventional resist ashing processes and may leave residue and particles on the wafer which may negatively impact yield of the integrated circuit.